Age and growth affect oleoresin yield from copaiba trees in the cerrado–Amazonia ecotone

Abstract

Copaiba trees, of the genus Copaifera (Fabaceae), produce an oleoresin that has pharmacological applications. The yield from the trees is very variable, and factors affecting production are still unknown. We evaluated the yield of oleoresin from Copaifera spp. in the Cerrado– Amazonia ecotone, as well as its relationship with the growth and age of trees. We sampled 30 Copaifera trees by extracting oleoresin for 24 h with a metal borer. Increment cores were collected from 15 trees to determine their age by counting growth rings and to calculate the mean annual increment of the diameter at breast height. The cylinders were sanded and the number of growth rings was counting with a magnifying glass (10x). The ages of trees from which increment cores were not collected were estimated by simple regression analysis. The proportions of productive and non-productive trees were recorded. The best adjusted model for age estimation showed R² adjust. = 0.616 and Syx% = 4.42. The average productivity of oleoresin was 0.124 L per day, and 30% of the trees were productive. The proportion of productive trees increased with increasing diameter at breast height and age, but after a point, increasing diameter was associated with reduced productivity. The mean annual increment had an inverse relationship with diameter for the productivity of oleoresin. The results suggest that other factors could be triggering and controling the oleoresin production and not only the age.